1. Field of the Invention
The present invention relates to electrically actuated switching devices or relays. In particular, the invention relates to a solid-state relay electrically actuated to open/close an electrical circuit in response to a control signal to disconnect/connect a first portion of an electrical circuit from/to a second portion of such a circuit. Particularly, but in a non-limiting manner, the invention relates to an electronic solid-state relay which can be used to electrically disconnect/connect an electric charge storage device or battery for electric or hybrid traction motor vehicles from/to a load.
2. Description of the Related Art
In applications in the automotive field, in particular in electric or hybrid traction vehicles, each motor vehicle is equipped with a source of electric charge or electric charge storage device or battery adapted to store the electrical energy used also for traction. Movement system for an electric or hybrid vehicle typically includes a loading assembly, in particular an electric motor adapted to generate the motion, driven by an inverter, which is electrically connected to a battery pack or assembly for storing the electrical energy. In particular, the electrical connection between the inverter and the battery pack is achieved by a direct current (DC) bus, generally referred to as DC-BUS or HV DC BUS by those skilled in the art.
The battery pack particularly comprises an electrochemical cell block adapted to supply the desired voltage and capacitance to the terminals of the direct current bus. The battery pack cells can be electrically disconnected from the loading assembly by the isolation devices, in particular relays.
In the automotive field, it is known to construct such relays by electromechanical devices, in particular for high currents, controlled by a Battery Management System or BMS, generally housed inside the battery pack itself. Such electromechanical relay devices for high currents used in the automotive field are not free from drawbacks.
Indeed, such relays have a large, heavy structure, comprising moving mechanical parts, which increases the size and overall weight of the battery system with which they are associated. Moreover, the presence of moving mechanical parts which are subject to deterioration over time or particular operating working conditions, such as for example the opening of the relay itself in the presence of high currents, could reduce the lifespan of the relay with respect to the working life of the battery.
Moreover, detecting the current which crosses the electromechanical relay when this is in the closed state is often needed in the movement system of an electric or hybrid traction vehicle. For such a purpose, such a system comprises a current measuring sensor implemented, for example, by a shunt resistor or a Hall effect sensor, associated with the direct current bus and controlled by the Battery Management System BMS. Such a sensor is an additional element of the system which further complicates the structure thereof.